/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.utils;

import org.apache.iotdb.db.engine.modification.Deletion;
import org.apache.iotdb.db.engine.modification.Modification;
import org.apache.iotdb.db.engine.querycontext.QueryDataSource;
import org.apache.iotdb.db.engine.storagegroup.TsFileResource;
import org.apache.iotdb.tsfile.file.metadata.AlignedChunkMetadata;
import org.apache.iotdb.tsfile.file.metadata.IChunkMetadata;
import org.apache.iotdb.tsfile.read.common.TimeRange;

import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;

public class QueryUtils {

    private QueryUtils() {
        // util class
    }

    /**
     * modifyChunkMetaData iterates the chunkMetaData and applies all available modifications on it to
     * generate a ModifiedChunkMetadata. <br>
     * the caller should guarantee that chunkMetaData and modifications refer to the same time series
     * paths.
     *
     * @param chunkMetaData the original chunkMetaData.
     * @param modifications all possible modifications.
     */
    @SuppressWarnings("squid:S3776") // Suppress high Cognitive Complexity warning
    public static void modifyChunkMetaData(
            List<? extends IChunkMetadata> chunkMetaData, List<Modification> modifications) {
        for (IChunkMetadata metaData : chunkMetaData) {
            for (Modification modification : modifications) {
                // When the chunkMetadata come from an old TsFile, the method modification.getFileOffset()
                // is gerVersionNum actually. In this case, we compare the versions of modification and
                // mataData to determine whether need to do modify.
                if (metaData.isFromOldTsFile()) {
                    if (modification.getFileOffset() > metaData.getVersion()) {
                        doModifyChunkMetaData(modification, metaData);
                    }
                    continue;
                }
                // The case modification.getFileOffset() == metaData.getOffsetOfChunkHeader()
                // is not supposed to exist as getFileOffset() is offset containing full chunk,
                // while getOffsetOfChunkHeader() returns the chunk header offset
                if (modification.getFileOffset() > metaData.getOffsetOfChunkHeader()) {
                    doModifyChunkMetaData(modification, metaData);
                }
            }
        }
        // remove chunks that are completely deleted
        chunkMetaData.removeIf(
                metaData -> {
                    if (metaData.getDeleteIntervalList() != null) {
                        for (TimeRange range : metaData.getDeleteIntervalList()) {
                            if (range.contains(metaData.getStartTime(), metaData.getEndTime())) {
                                return true;
                            } else {
                                if (range.overlaps(new TimeRange(metaData.getStartTime(), metaData.getEndTime()))) {
                                    metaData.setModified(true);
                                }
                            }
                        }
                    }
                    return false;
                });
    }

    public static void modifyAlignedChunkMetaData(
            List<AlignedChunkMetadata> chunkMetaData, List<List<Modification>> modifications) {
        for (AlignedChunkMetadata metaData : chunkMetaData) {
            List<IChunkMetadata> valueChunkMetadataList = metaData.getValueChunkMetadataList();
            // deal with each sub sensor
            for (int i = 0; i < valueChunkMetadataList.size(); i++) {
                IChunkMetadata v = valueChunkMetadataList.get(i);
                if (v != null) {
                    List<Modification> modificationList = modifications.get(i);
                    for (Modification modification : modificationList) {
                        // The case modification.getFileOffset() == metaData.getOffsetOfChunkHeader()
                        // is not supposed to exist as getFileOffset() is offset containing full chunk,
                        // while getOffsetOfChunkHeader() returns the chunk header offset
                        if (modification.getFileOffset() > v.getOffsetOfChunkHeader()) {
                            doModifyChunkMetaData(modification, v);
                        }
                    }
                }
            }
        }
        // if all sub sensors' chunk metadata are deleted, then remove the aligned chunk metadata
        // otherwise, set the deleted chunk metadata of some sensors to null
        chunkMetaData.removeIf(
                alignedChunkMetadata -> {
                    // the whole aligned path need to be removed, only set to be true if all the sub sensors
                    // are deleted
                    boolean removed = true;
                    // the whole aligned path is modified, set to be true if any sub sensor is modified
                    boolean modified = false;
                    List<IChunkMetadata> valueChunkMetadataList =
                            alignedChunkMetadata.getValueChunkMetadataList();
                    for (int i = 0; i < valueChunkMetadataList.size(); i++) {
                        IChunkMetadata valueChunkMetadata = valueChunkMetadataList.get(i);
                        if (valueChunkMetadata == null) {
                            continue;
                        }
                        // current sub sensor's chunk metadata is completely removed
                        boolean currentRemoved = false;
                        if (valueChunkMetadata.getDeleteIntervalList() != null) {
                            for (TimeRange range : valueChunkMetadata.getDeleteIntervalList()) {
                                if (range.contains(
                                        valueChunkMetadata.getStartTime(), valueChunkMetadata.getEndTime())) {
                                    valueChunkMetadataList.set(i, null);
                                    currentRemoved = true;
                                    break;
                                } else {
                                    if (range.overlaps(
                                            new TimeRange(
                                                    valueChunkMetadata.getStartTime(), valueChunkMetadata.getEndTime()))) {
                                        valueChunkMetadata.setModified(true);
                                        modified = true;
                                    }
                                }
                            }
                        }
                        // current sub sensor's chunk metadata is not completely removed,
                        // so the whole aligned path don't need to be removed from list
                        if (!currentRemoved) {
                            removed = false;
                        }
                    }
                    alignedChunkMetadata.setModified(modified);
                    return removed;
                });
    }

    private static void doModifyChunkMetaData(Modification modification, IChunkMetadata metaData) {
        if (modification instanceof Deletion) {
            Deletion deletion = (Deletion) modification;
            metaData.insertIntoSortedDeletions(deletion.getTimeRange());
        }
    }

    public static void fillOrderIndexes(
            QueryDataSource dataSource, String deviceId, boolean ascending) {
        List<TsFileResource> unseqResources = dataSource.getUnseqResources();
        int[] orderIndex = new int[unseqResources.size()];
        AtomicInteger index = new AtomicInteger();
        Map<Integer, Long> intToOrderTimeMap =
                unseqResources.stream()
                        .collect(
                                Collectors.toMap(
                                        key -> index.getAndIncrement(),
                                        resource -> resource.getOrderTime(deviceId, ascending)));
        index.set(0);
        intToOrderTimeMap.entrySet().stream()
                .sorted(
                        (t1, t2) ->
                                ascending
                                        ? Long.compare(t1.getValue(), t2.getValue())
                                        : Long.compare(t2.getValue(), t1.getValue()))
                .collect(Collectors.toList())
                .forEach(item -> orderIndex[index.getAndIncrement()] = item.getKey());
        dataSource.setUnSeqFileOrderIndex(orderIndex);
    }
}
